1. Field
Embodiments of the inventive concept relate to a nonvolatile memory device, more particularly, to a nonvolatile memory device with a three-dimensional structure capable of improving electrical characteristics and a method of fabricating the same.
2. Description of the Related Art
In general, nonvolatile memory devices can electrically erase and program data and can retain data even if a power source is interrupted. Nonvolatile memory devices are increasingly being used in various fields.
These nonvolatile memory devices are provided with various types of memory cell transistors. The nonvolatile memory devices include flash memory devices. Flash memory devices may be classified into types, namely, NAND type and NOR type, according to cell array structures. The NAND-type flash memory devices and the NOR-type flash memory devices have both advantages and disadvantages in high integration and high-speed performance, respectively.
Specifically, NAND-type flash memory devices are advantageous for high integration due to a cell string structure in which a plurality of memory cell transistors are connected to each other in series. In addition, since the NAND-type flash memory devices utilize an operation which simultaneously changes all information stored in the plurality of memory cell transistors, an information update speed of the NAND-type flash memory devices is far faster than that of the NOR-type flash memory device. Due to the high integration and fast update speed, the NAND-type flash memory devices are mainly used for portable electronic products that require a mass storage device such as a digital camera or an MP3 player.
Research and developments have been actively made in order to promote and improve advantages of the NAND-type flash memory devices. Specifically, developments have been made with regard to NAND-type flash memory devices with three-dimensional structures.